A chart circulated by a leading immigration reform organization makes a basic, but compelling case that the new law passed -- though not implemented -- in Arizona could cause an increase rather than a drop in crime.

The non-profit group America's Voice sent out a chart on Wednesday, documenting the change in violent crime levels in various Arizona police jurisdictions from 2002 through 2009. The numbers tell two interesting stories.

The first is that, by and large, crime is down across the board. In Arizona as a whole, it has dropped 12 percent in the past seven years. But in major Maricopa County cities with their own police forces -- Phoenix, Mesa, Scottsdale and Tempe -- the rate has dropped even faster. (The group measured within Maricopa County because it is the epicenter of the immigration debate. But in Tuscon, which is not in the county, there has also been a drop in the crime rate since 2002, according to law enforcement statistics).

Those findings alone suggest that the systemic violence often cited as the compelling argument for stricter border laws may be overblown.

But the more telling number may be the crime statistics for the portion of Maricopa County that is under the purview of controversial Sheriff Joe Arpaio. According to data compiled by America's Voice, crime in that area has actually increased 58 percent since 2002.

Arpaio is considered something of a visionary among conservatives with respect to his approach to immigration. Many of his reforms, indeed, have served as a basis for the law that Gov. Jan Brewer tried to implement statewide. But he has clashed with other sheriffs over his methods, with some complaining that such broad anti-immigration policies put an overwhelming burden on law enforcement officials while producing social friction rather than safety.

America's Voice's chart isn't perfect. For one, Arpaio's domain is much smaller than those of the major cities within the county. Crime as a whole remains lower under his watch than, say, in Phoenix (only it's increasing as opposed to decreasing over time). Moreover, not every factor responsible for the violent crime level can or should be tied to immigration.

But the group's underlying point is that the discussion around immigration policy both in Arizona and the United States at large needs to be reoriented. And the raw percentages of violent crime statistics shown in the chart have that effect.